This invention relates generally to fluid flow control apparatus, and more particularly to a diverter box for reversing the flow of fluid through a heat exchanger.
Flow control apparatus or devices are frequently employed to periodically reverse the flow of a fluid through a heat exchanger to dislodge and flush debris therefrom. For example, often water from natural sources such as rivers and lakes typically includes a significant amount of particulates or debris; and, when such water is conducted through the tubes of a heat exchanger, these particulates and debris tend to collect or accumulate in the tubes, restricting the water flow therethrough and thus impairing the efficiency of the heat exchanger. Reversing the water flow through the heat exchange tubes tends to dislodge debris therefrom, cleaning the tubes and enabling the tubes to operate with greater efficiency.
Prior art devices for reversing the flow of fluid through a heat exchanger are often cumbersome and involve numerous moving parts. In addition, debris in the water flowing through prior art flow control apparatus may collect and accumulate therein, impeding operation thereof. This may necessitate frequent cleaning of the apparatus, and this often involves expensive manual labor and requires temporarily taking the flow control apparatus out of operation. Moreover, prior art devices generally require positive action by a drive or power means both to change the device to a reverse flow position and to return the device to a normal flow position. This raises the possibility that, in case of a failure of the drive or power means, the flow control device may become locked in the reverse flow position, which typically results in the heat exchanger operating less efficiently than when the flow control device is in its normal flow position.